Chem Chem Flashcards Preview

Chemistry Unit > Chem Chem > Flashcards

Flashcards in Chem Chem Deck (45):

What is an element?

any material that is made up of only one type of atom


what is a atom?

the smallest particle of an element that has all of the elements chemical properties


What particles are atoms made of?

electrons, protons, and neutrons


What is the atomic number?

the number of protons in the nucleus of an atom. (upper left hand corner)
atomic number = protons
protons= number of electrons


What is the atomic mass?

the total number of protons and neutrons. atomic number- atomic mass(# below element)= neutrons .


What is an isotope?

its when an element has equal numbers of protons but different numbers neutrons in their nuclei. (normally a radioactive form of an element)


What is a period and what is a group on the periodic table?

what is the trend for atomic size on the periodic table?

period- a horizontal row
group- a vertical column

- going horizontal, decrease in size, going down/vertical increase in size


What is an inner transition metal?

one of a group of chemical elements on the periodic table. They include elements 58-71 (lanthanides) and 90-103 (actinides). lanthanides are similar and actinides are radioactive.


What is radioactivity?

the process whereby unstable atomic nuclei break down and emit radiation


What is a alpha ray?

alpha- carry a positive electrical charge. combo of 2 protons and 2 neutrons. its large so its hard to go through things but it can damage the surface of things.


what is a beta ray?

carry a negative charge, originate inside the nucleus. able to penetrate paper or clothing and fairly deeply into skin


what is a gamma ray?

carry no charge. are the high frequency electromagnetic radiation emitted by radioactive elements. can penetrate most materials.


What is a nucleon?

What is the strong nuclear force?

- a collective name for protons and neutrons.

-a force that holds quarks together in elementary particles. it is the strongest force known in nature.


How do you find alpha decay?

you use 4/2 He.
226/88 Ra becomes=
222/86 Rn... you subtract 4 on the top and subtract 2 on the bottom


How do you find beta decay?

you use o/-1 e
3/1H becomes
3/2 He... the top stays the same and the bottom you add one


What is nuclear fission?

either a nuclear reaction or a radioactive decay process in which the nucleus of an atom splits into smaller parts. The fission process often produces free neutrons and gamma photons, and releases a very large amount of energy.
-used for atomic bombs


What does E=mc2 mean?

E= energy that any mass has at rest
m= mass
c= speed of light
c2= proportionally constant of energy and mass


Where does nuclear fusion occur?

extremely high temps found in the sun and other stars.
-used for hydrogen bombs
-more powerful
-2 light nuclei combine to form a heavy nucleus


what is matter?

physical substance that occupies space and possesses rest mass


what is a pure substance?

a substance that consists of only a single element or a single compound (element and compound)


What is a element?

any material that is made up of only one type of atom--pure
examples: gold, sulfur, nitrogen


what is a compound?

a material in which atoms of different elements are bonded to one another.
examples- salt, carbon dioxide, ammonia


what is a homogenous mixture?

a mixture in which the components are so finely mixed that the composition is the same through out--impure


what is a heterogenous mixture?

a mixture in which the various components can be seen as individual substances--impure


what is a solution?

a homogenous mixture in which all components are in the same phase- examples- air, salt water, white gold


what is a suspension?

a homogenous mixture in which the various components are in different phases- examples- milk, blood, fog


whats the difference between a solution and a suspension?

particle sizes. solution is a mixture of ions or molecules and it looks transparent. suspension has bigger particle sizes and it looks cloudy


How do you find the concentration of a solution?

amount of solute/ around of solution


How do you find molarity?

# of moles of solute/ liters of solution


Why won't a power plant- nuclear reaction to explode?

-The U235 are highly diluted with U238
-Two separate water systems are used so that no radioactivity reaches the turbine or the outside environment


Whats an ionic bond?

-when one atom is + charged ( the one that gives) and the other is - charged (the one that receives) its the opposite charge that attracts and holds them together


what is a covalent bond?

- a chemical bond that involves the sharing of electron paris between atoms. holds together by a mutual attraction


what is a polar covalent bond?

- a pair of electons is unequally shared between two atoms.


what is a metallic bond?

- chemical bond that holds the atoms of a metal together.


How do you form ionic compounds?

look at the columns on the table: +1, +2..... +3, x, -3, -2, -1, x. then you add it up. example:
Na + Cl = Na (+1) + Cl (-1) = NaCl
everything has to come out to zero


How does the polarity of a molecule affect how molecules are attracted to each other?

the positive and negative ends of polar molecules attract each other.


What is a dipole?

positive electric charge is separated from a concentration of negative charge


Whats a ion-dipole?

attraction between an ion and and the dipole of a polar molecule


whats a dipole-dipole?

an attraction between two polar molecules


whats a dipole-induced dipole?

attraction between a permanent dipole and the induced dipole


what is a induced dipole-induced dipole?

a temporary dipole induces a nonpolar molecule to a induced dipole


Whats solubility?

Why do substances have different solubility?

-the ability of a solute to dissolve in a given solvent

- attractions between solute and solvent particles, point of saturation and temp


Why does soap work?

what are the two parts in the soap molecule?

- it has both polar and non polar properties

-a long non polar tail of carbon and hydrogen atoms and a head containing at least one ionic bond


soap process

attracts non polar grime via induced dipole-induced dipole attraction. W/ the non polar tails facing inward toward the grime, the polar heads are all directed outward, where they are attracted to water molecules by strong ion-dipole attractions. if water is going, combo goes down drain.


soap history---say wha??

For the past several centuries, soaps have been prepared by treating animal fats with sodium hydroxide, NaOH, also known as caustic lye. In this reaction, which is still used today, each fat molecule is broken down into 3 fatty acid soap molecules and 1 glycerol molecule